August 2019 13
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Turret Stop
Although I have specifi ed six locations
for the detent balls and springs, I have
found that using three is suffi cient for
very positive indexing. However, I would
still advise drilling and tapping at all six
positions just in case you feel that an even
more positive action suits you.
You will notice that this set-up only uses
one tee-slot on the cross slide so care needs
to be taken to avoid the VDH moving. I
can’t recall having any problems with such
an arrangement, but if you have concerns
simply use the tailstock to ‘push’ the
workpiece against the drill.
During this operation please ensure that
your springs and balls fi t into the holes
without any resistance.
That done, now is an opportunity to
stamp all six positions with a number or any
other identifi cation mark that suits you. I
used 1/8” number stamps, placed clockwise
looking from the tailstock towards the
headstock, so eff ectively if using ‘No 1’
position, you will rotate the turret away
from you to use ‘No 2’ position, and so on.
The fi rst thing to do is ensure that the
numbers are stamped to coincide with the
length screws. There are several ways of
doing this depending on the equipment
you have available. I have used the VDH
and 3-jaw in conjunction with the pillar tool
to stamp the numbers, although it is also
possible to use an angle plate mounted on
the cross-slide in conjunction with the pillar
tool mounted on the lathe bed. Of course,
you could always stamp the numbers
freehand, but I’m not brave enough to
attempt that.
If using the set-up that I’m suggesting
here, the fi rst thing that we must do is to
ensure that the tapped holes for the length
screws are correctly orientated in the chuck,
so the method shown in photo 7 should
help. Simply fi t a couple of screws into the
threaded holes, and then use a square to
set the vertical.
Before going too far with this operation
it may be worth using a simple drawbar
through the VDH mandrel to secure the
turret body in the lathe chuck, aft er all if
you’re planning to use large number stamps
and a 2lb hammer the turret body could
become dislodged.
To stamp the numbers, align the turret
body with the pillar tool and stamp away,
photo 8. The number stamping operation
will raise the surrounding metal, so when
all six have been done to your satisfaction,
dress this back and polish out those lightly
scribed lines.Turret - small parts (fi g. 3)
Making these items is a straightforward
turning job. Ideally they should be made at
the same time as item 6.6 which is the stop
screw as it is identical apart from the thread
length (which is 2.25” long rather than 3.5”
long).
Turn down and thread 5/16” BSF, aiming
for a nice smooth thread without any
sloppiness. and then knurl the head. Aft er
parting off , the cut end can be faced off
and a couple of small chamfers at the ends
of the knurled section will make the screws
more pleasant to use. All that needs to bedone now is to drill the cross-holes 2.4mm
which will provide a nice easy fi t for a 3/32”
tommy bar.
3.2 Locking collar
The locking collars are basically knurled
nuts with 6 tommy bar holes around the
periphery and are straightforward to make.
The total requirement for these is seven,
as we will need one for use as part of the
stop assembly, so it is worth making them
all now.
If I were making these again, I would fi rst
produce a number of threaded, knurled
discs from 5/8” diameter bar stock - free
cutting steel is perfectly adequate here.
Place a length of material in the 3-jaw
chuck, face and turn the shoulder on the
outer end. The bar can now be threaded
5/16” BSF and the outer surface knurled,
breaking the edges with a small chamfer.
Following this I would part-off from the
parent material, adding suffi cient length for
facing to clean-up.
Now prepare a mandrel which has been7 8
9
Threading the locking collarSetting the turret body in the VDH ready for number stamping (posed) Number stamping the length screw (indexing) positions (posed)